﻿/* Copyright 2010-present MongoDB Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/

using System;
using System.IO;

namespace MongoDB.Driver.Core.Authentication.Oidc
{
    internal sealed class GcpOidcCallback : HttpRequestOidcCallback
    {
        private readonly string _tokenResource;

        public GcpOidcCallback(string tokenResource)
        {
            _tokenResource = tokenResource;
        }

        protected override (Uri Uri, (string Key, string Value)[] headers) GetHttpRequestParams(OidcCallbackParameters parameters)
        {
            var metadataUrl = $"http://metadata/computeMetadata/v1/instance/service-accounts/default/identity?audience={Uri.EscapeDataString(_tokenResource)}";

            return (new Uri(metadataUrl), new[] { ("Metadata-Flavor", "Google") } );
        }

        protected override OidcAccessToken ProcessHttpResponse(Stream responseStream)
        {
            using var responseReader = new StreamReader(responseStream);
            return new OidcAccessToken(responseReader.ReadToEnd(), null);
        }
    }
}
